• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.187-193
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• 2020

Floating point arithmetic in microprocessor is the computation of addition, subtraction, multiplication, and division of floating point data to improve accuracy. In general, when designing a processor, floating point instructions are often excluded because of its complexity and only integer instructions are provided. However, in order to carry out the computations for not only engineering and technical operations but also artificial intelligence and neural networks that are in the spotlight today, floating point operations must be included. In this paper, we design a 32-bit ARMv4 family of processors with floating-point arithmetic instructions using VHDL and verify with ModelSim. As a result, ARM's floating point instructions are successfully executed.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.620-620
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• 2012

에너지 다소비원인 공공하수처리시설은 기후협약에 따른 온실가스 저감시설로서의 그 역할이 증대되고 있다. 환경부는 '하수처리시설 에너지 자립화 계획'을 통해 2015년까지 에너지 자립율 18%를 목표로 하고 있으며, 이를 위해서는 신재생에너지를 이용한 능동적 에너지 생산이 필요하다. 소수력발전은 공급 안정성이 우수하고 소수력발전은 일정한 처리수가 방류되는 하수처리장에 적용되었을 때 그 가동율은 하천에서의 소수력발전에 비하여 우수하다고 알려져 있으며, 향후 하수처리장에 널리 보급될 수 있는 청정에너지원이라고 할 수 있다. 본 연구에서는 기흥 레스피아에서 처리되는 하수를 이용한 소수력발전이 검토되었다. 최근 5년간 방류량 자료를 살펴보면 기흥 레스피아의 일평균 실제 처리량은 약 $30,000m^3/day$로 나타났으며, 우수 유입과 물 사용량이 증가하는 여름 및 가을에 처리량이 증가하였다. 설계유량은 유량변화에 따른 누적 확률밀도와 유량지속곡선에 근거해 산정하였으며, 시간빈도(T)로 보았을 때 26%의 유량이 지속되는 $0.35m^3/s$를 설계유량으로 선정하였다(그림 1). 또한 이를 기반으로 성능특성을 분석한 결과, 단위낙차당 수차발전기의 용량은 2.4kW이며, 시스템 가동율은 74%, 그리고 연 전력생산량은 16.6MWh로 나타났다(그림 2).

• Journal of Korea Water Resources Association
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• v.42 no.12
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• pp.1029-1038
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• 2009

Recently, it is expected that small hydropower (SHP) could potentially provide sufficient amounts of alternative energy in Korea where there is an abundance of potential sites and where social efforts are being made to reduce the emissions of green house gases. In the past, the resources survey for SHP development has been carried out using onsite surveys and paper maps, which incurred a great deal of time and cost. Furthermore, the tools for decision making such as determining development priorities or evaluating feasibility have been considered only economic aspect and focused on the performance characteristics of power generation. However, as the concept of sustainable development has been being advanced in recent years, especially focused on human-social, environmental and ecological in addition to economical sector; the consideration of these multiple criteria has become essential for sustainable SHP development. This study aims to propose the spatial multi-criteria decision making (MCDM) methodology for determining priorities among a number of locations on the planning stage of SHP development using AHP and GIS. The proposed methodology is applied for determining development priorities among the SHP locations in Cho River basin and this study presents the detailed spatial information data and the results of development priorities. As a fundamental work, this study will be beneficial to the future activation of SHP development and will help the decision making in evaluating the feasibility of SHP development.

• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.26-30
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• 1998

Tetradecapeptide, Mastoparan B(MP B) and its [$Ala^2$]-, [$Ala^4$]-, [$Ala^6$]-, [$Ala^9$]-MP B derivatives were synthesized, and then their antibacterial and hemolytic activities were assayed to examine the effect of hydrophobicity and amphiphilicity on the MP B-induced those activities. MP B and more hydrophobic [$Ala^2$]-, [$Ala^4$]-MP B showed stronger antibacterial activity and less hydrophobic [$Ala^6$]-MP B than MP B did similar or weaker activity, so more hydrophobic [Ala]-MP B derivative had stronger activity. But more hydrophobic [$Ala^9$]-MP B than MP B showed weaker activity because of its Trp substitution by Ala. On the other hand, [$Ala^2$]- and [$Ala^4$]-MP B showed 100.0% and 69.4% hemolytic activity, but [$Ala^6$]-MP B did the weakest activity(6.1%) and [$Ala^9$]-MP B, weaker activity(26.0%) than MP-B. Therefore, more hydrophobic [Ala]-MP B derivative had stronger activity and the effect of amphiphilicity on the activity was weak.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.49-59
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• 2008

SIFT(Scale Invariant Feature Transform) is an algorithm to extract vectors at pixels around keypoints, in which the pixel colors are very different from neighbors, such as vortices and edges of an object. The SIFT algorithm is being actively researched for various image processing applications including 3-D image constructions, and its most computation-intensive stage is a keypoint localization. In this paper, we develope a fixed-point model of the keypoint localization and propose its efficient hardware architecture for embedded applications. The bit-length of key variables are determined based on two performance measures: localization accuracy and error rate. Comparing with the original algorithm (implemented in Matlab), the accuracy and error rate of the proposed fixed point model are 93.57% and 2.72% respectively. In addition, we found that most of missing keypoints appeared at the edges of an object which are not very important in the case of keypoints matching. We estimate that the hardware implementation will give processing speed of $10{\sim}15\;frame/sec$, while its fixed point implementation on Pentium Core2Duo (2.13 GHz) and ARM9 (400 MHz) takes 10 seconds and one hour each to process a frame.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.79-86
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• 2018

In this study, emulsion type hydrophobic admixture was prepared by mixing polyvinyl alcohol surfactant, polymethyl hydro-siloxane and meta kaolin, and the compressive strength and mechanical properties such as permeability and contact angle test of the mortar were evaluated. The developed hydrophobic admixture showed no decrease in strength and the mortar specimen with magnesium oxide developed the early strength. In the case of permeability, total seepage was significantly decreased when the hydrophobic admixture was directly mixed with the mortar, but the effect of meta kaolin contained in hydrophobic admixture was not significant. The surface of specimens coated with hydrophobic admixture shows that the contact angle on the surface was highly increased compared with reference mortar specimen. Further researches to obtain the optimum mix proportion of the PVA fiber, nano-silica and meta kaolin for producing the super-hydrophobic surface are required.

• Journal of Educational Research in Mathematics
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• v.17 no.3
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• pp.233-251
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• 2007

The purpose of this study was to propose instructional methods using base-ten blocks in teaching the division of decimal for 5th grade students by analyzing the process of their conceptual comprehension. The students in this study were found to understand the two main meanings of the division of decimal, distribution and area, by modeling them with base-ten blocks. They were able to identify the algorithm through the use of base-ten blocks and to understand the principle of calculations by connecting the manipulative activities to each stage of algorithm. The students were also able to determine using base-ten blocks whether the results of division of decimal might be reasonable. This study suggests that the appropriate use of base-ten blocks promotes the conceptual understanding of the division of decimal.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.169-177
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• 2011

As demand for efficiency in handling dynamic XML data grows, new dynamic XML labeling schemes have been researched. The key idea of the dynamic XML labeling scheme is to find ancestor-descendent-sibling relationships and to minimize memory space to store total label, response time and range of relabeling incurred by update operations. The prime number labeling scheme is a representative scheme which supports dynamic XML documents. It determines the ancestor-descendant relationships between two elements by a simple divisibility test of labels. When a new element is inserted into the XML data using this scheme, it does not change the label values of existing nodes. However, since each prime number must be used exclusively, labels can become significantly large. Therefore, in this paper, we introduce a novel technique to effectively reduce the problem of label overflow. The suggested idea is based on tree decomposition. When label overflow occurs, the full tree is divided into several sub-trees, and nodes in each sub-tree are separately labeled. Through experiments, we show the effectiveness of our scheme.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.459-466
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• 2011

In this study, the resources investigations of small hydropower generation were carried out for the five proposed sites in northern Gyeong-buk area. They consisted of the discharge measurements, rating-curve, flow duration curves, electricity generation, and economic analysis, respectively. The basic data were suggested to select the optimal small hydropower sites in northern Gyeong-buk area. The sites for Yecheon Gun and Munsu Myeon as a result are the best proposed ones using economic analysis. We considered, however, that the finacial benefit for small hydropower development may be small under 500 kW facility. The optimal proposed site over 500 kW facility was suggested as Yeongyang Gun in this study.

• Journal of the Korean School Mathematics Society
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• v.18 no.4
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• pp.353-370
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• 2015

This study was conducted as a qualitative case study that explored how gifted 3rd-grade elementary school children who had learned the primary concepts of division and fraction, when they studied contents about decimal, formed the transformed primary concept and transformed schema of decimal by the learning of accurate primary concepts and connecting the concepts. That is, this study investigated how the subjects attained relational understanding of decimal based on the primary concepts of division and fraction, and how they formed a transformed primary concept based on the primary concept of decimal and carried out vertical mathematizing. According to the findings of this study, transformed primary concepts formed through the learning of accurate primary concepts, and schemas and transformed schemas built through the connection of the concepts played as crucial factors for the children's relational understanding of decimal and their vertical mathematizing.